A bicycle's wheels are held straight, or true, by even tension on the spokes pulling from the hub of the wheel to the rim. A good wheel must have enough equal tension on the spokes pulling from each side of the hub to the rim in order for the wheel to stay straight, or true, under pedal loads and in the event of a blow to the wheel.
When the wheel has been well used, or a blow has been impacted to the wheel, the wheel will then develop a wobble, which is then said to be an “un-true wheel”. To fix an un-true wheel it is required to re-tension the spokes in an appropriate fashion, which will pull the rim back into place. In order to correct the right spoke tension an indicator must be made on the area of the rim, which is out of true.
The operation of truing a wheel traditionally requires the use of a truing stand, which is a bench-top stand typically used in a bicycle repair shop or bicyclist's garage. Use of a truing stand requires that the wheel must be removed from the bicycle and installed into the truing stand. However, as trail and mountain bicycling has gained in popularity, damage to bicycle wheels occurs frequently while riding in rugged terrain. This poses a major inconvenience to mountain or road cyclists with damaged wheels in the field as the bicycle can no longer be ridden, ending the outing, and then the task must be undertaken of walking or carrying the bicycle to a vehicle that can transport it to a bicycle repair shop, not to mention the cost of the repair.
Those skilled in the art will appreciate that a very useful tool for the mountain or trail bicyclist, and even for the road cyclist, therefore would be a portable truing tool that is compact, light-weight and easy to transport while riding with minimal gear, and simple to use, thus allowing truing repairs to be done in the field in minutes by one with rudimentary repair skills. Portable truing tools for this purpose have been described in the patent literature, but have flawed designs that have prevented them from being successfully brought to market. Such earlier designs have never materialized in the form of commercially-available portable truing tools for bicycles in recent memory. Examples of earlier frame-mountable truing tools designed for bicycle wheels and other uses of spoked wheels include U.S. Pat. No. 640,607 to Wardwell, U.S. Pat. No. 1,073,042 to Heller, U.S. Pat. No. 1,450,518 to Schwartz, U.S. Pat. No. 3,956,829 to Moxon, U.S. Pat. No. 5,201,782 to Bartlett, U.S. Pat. No. 5,243,765 to Lynch, U.S. Pat. No. 5,193,283 to Hsiao, and U.S. Pat. No. 5,539,988 to Braun. These cited tools have basic drawbacks that render them inefficient and unwieldy. The common drawbacks are limited spatial maneuverability of the tool to align the truing gauge portion of the tool next to the wheel rim, a fixed gauge indicator, being rigidly affixed to the rest of the tool, is prone to frequent shock from contacting a untrue section of a rotating wheel rim that will push on the gauge and move it inadvertently out of alignment, causing inaccurate gauging and frustrating the truing procedure. Others suffer from flimsy and clumsy design, being composed of thin members prone to misalignment due to simple vibration from the turning wheel. Alignment of the gauge portion of the tools is tedious, requiring multiple adjustments of the support members for tools offering some maneuverability of the gauge, requiring changing the angular relationship between them while untightening and re-tightening thumb screws. Another major drawback of all of the truing tools cited above due to the rigid nature of the gauge indicator portions, which normally are conical tips or blade-like straight edges solidly connected to the rest of the tool. When in physical contact, these indicators will scratch or otherwise mar the surface finish of wheel rims, which are mostly composed of soft materials such as aluminum or carbon fiber composites, or even painted finishes. Finally, with the exception of Bartlett, Hsaio and Lynch, most of the cited frame-mountable truing tools are not compactly storable when not in use, and therefore not well suited for transporting while on biking outings where it is desirous to carry a minimal amount of gear.